Electric circuit breaker



1949- H. A. H. NIJLAND I ELECTRIC CIRCUIT BREAKER File d Dec. 19, 1946 Patented Jan. 11, 1949 ELECTRIC CIRCUIT BREAKER Hendrik A. H. Nijland, Laren, Netherlands Application December 19, 1946, Serial No. 717,226 In the Netherlands January 16, 1946 This invention relates to a circuit-breaker for high voltage of the kind comprising a stationary supporting body, leading-in conductors and a contact make and breakelement provided with a tube of insulating material, within which fixed switching contacts and one or more movable switching contacts cooperating therewith are accommodated, said insulating tube supporting contact means connected to the fixed switching contacts and so engaging contact means secured to the leading-in conductors as to permit the contact make and break element to be entirely withdrawn from and inserted into the supporting body, while the leading-in conductors are alive.

To illustrate the above, reference is had to the drawing, which by way of example shows two embodiments of the invention.

In this drawing:

Fig. 1 is a vertical sectional view of a circuitbreaker in accordance with the invention,

Fig. 2 is a sectional view on the line III-I1 of Fig. 1, and

Fig. 3 is a sectional view after withdrawal, from the stationary supporting body, of the contact make and break element of another circuitbreaker according to the invention.

The contact make and break element of the represented circuit-breakers consists of switching contacts I and 2 and a movable contact-rod 3 cooperating therewith. Said contact-rod is connected, through an insulator 3', to an operating rod 3". The fixed switching contacts are spaced apart from one another and supported by insulating tubes 4 and 5. Said tubes separate the compartment in which the switching operation is carried out from the surroundings. The contact make and break element suspends from a cover 6, on which the operating mechanism (shown in dash lines) of the movable contact-rod is mounted. Said element projects into a double walled tubular supporting body which is open at both ends. Said body is provided with a metal outer wall I, an inner wall composed of insulating tubes 8, 9, I and screen-shaped contact-rings II, I2 and an insulating fluid of constant and high disruptive strength, e. g. a gas, a liquid, such as mineral oil, or a solid mass, in the space between said walls. The leading-in conductors I 4, I5 are passed through insulators in the outer wall I 2 Claims. (01. 200-48) and connected to the contact rings II, I2. At its outer surface the contact make and break element is provided with resilient contact means I6, II, which are permanently connected to the fixed switching contacts I and 2 and constitute a disengageable sliding connection with the contact-rings II, I2. The contact make and break element may be entirely withdrawn from or inserted into the supporting body, while said contact-rings and said leading-in conductors are alive.

Consequently, this circuit-breaker may be directly and permanently connected to a system of distributing busbars and/or cables. The screen-shaped contact-rings II and I2 force the electric field between the live parts of the contact make and break element and the outer wall 'I as much as possible into the space I3.

The circuit-breaker according to Fig. 3 diiiers from that according to Fig. 1 herein, that the contact-rings II and I2 are conductively connected to individual screens I8 and I9 arranged within the compartment I3. Moreover, the double walled tank is closed on its bottom side.

It will be understood that the nature of the circuit-breaker is of no importance to the invention. The circuit-breaker proper may be of the oil-blast, the gas-blast, the expansion type, etc.

What I claim is:

1. A metal-clad circuit-breaker for high voltage comprising in combination a stationary supporting body having a metallic outer wall and an inner wall of insulating material defining a space for an insulating fluid of constant and high quality, insulated leading-in conductors extending through said outer Wall, contact means connected to said conductors and projecting into the central space of said body, metal screens conductively connected to said contact means and mounted to force the electric field of greatest intensity from said central space into said space between said outer and inner wall and a contact make and break element comprising a tube of insulating material, cooperating switching contacts mounted on said tube, certain of said switching contacts being movable and the remaining switching contacts being stationary with regard to said tube, and contact members supported by said tube and projecting into the central space of said supporting body, said contact members being connected to said relatively stationary switching contacts and so engaging the contact means secured to the leading-in conductors to permit said contact make and break element to be entirely withdrawn from and inserted into the supporting body, while the leading-in conductors are alive.

2. A circuit-breaker as claimed in claim 1, in which in working condition of the circuit-breaker the insulating fluid within the central space of the supporting body and outside the contact make The following references are of record in the file of this patent:-

UNITED STATES PATENTS 10 Number Name Date 2,039,071 Dumn Apr. 28, 1936 2,261,720 Dufling et a1. Nov. 4, 1941 2,313,571 Nijland' Mar. 9, 1943 

